This invention relates to ultra high-strength hydraulic cement compositions (say, for the production of ultra high-strength hydraulic concrete) and more particularly to ultra high-strength hydraulic cement compositions having simultaneously a plurality of specified characteristics that are desirable to such compositions.
Ultra high-strength hydraulic cement compositions are produced by kneading water and cement together at a smaller mixing ratio than for the production of normal-strength hydraulic cement compositions. Because of their very nature, these ultra high-strength hydraulic cement compositions generally have several problems such that it takes a long time for the kneading, that the drop in fluidity with time (hereinafter referred to as the slump loss) is large, that the viscosity is too high, that the autogeneous shrinkage of the hardened object obtained from them is too large and that the strength of such a hardened object is not sufficiently high. In view of such problems, Japanese Patent Publication Tokkai 6-191918 and U.S. Pat. No. 5,466,289 disclosed the use of ultra high-quality cement dispersants as admixtures and Japanese Patent Publications Tokkai 2001-220194, 2001-48620 and 2001-278653 disclosed the use of shrinkage reducing agents as admixtures, but these prior art ultra high-strength hydraulic cement compositions cannot simultaneously solve all of the plurality of problems described above.